[melling]

Nope, air transportation is not a major contributor to CO2.

There are over 100,000 flights daily. They account for about 2.5% of CO2 emissions yearly.

You know what is? Coal power plants that generate electricity.

Maybe we should focus on electricity generation from coal. I’m a little surprised that more hasn’t been done.

https://www.carbonbrief.org/mapped-worlds-coal-power-plants

13 years ago Google attempted their RE<C project.

https://www.forbes.com/sites/williampentland/2014/11/30/why-...

[mrpopo]

Air transportation is a major contributor to CO2, if you limit the scope to the people who use it. It is estimated that about 80% of the world's adults have never taken a flight, and 94% of the world's adults have not taken a flight in over a year.

So, the real picture is that this 2.5% of global CO2 emissions are caused by as few as 6% of the population, who also are incidentally the richest and bear a high personal carbon footprint in other domains than transportation.

EDIT: I'll add to this that the aviation sector is growing, and therefore its global contribution to GHG emissions will grow as well in the future. Discounting the carbon footprint of the aviation sector based on today's numbers is a mistake.

[cletus]

The real villain here is coal-powered planes!

Ok, in all seriousness, the efficiency story for air travel is... complicated. So you claim planes account for 2.5% of CO2 emissions but air travel and transport is still a relative luxury enjoyed by a privileged few so that's not necessary accurate.

I found this [1] that shows planes to be much worse than automobiles (per passenger per km) but again, it's complicated.

Personally I don't mind the investment in supersonic travel. After all, it's hard to know what fruit this will ultimately bear. Some people have asked what's the difference between crossing the Atlantic in 4 hours instead of 8? It's the difference between able to go for the day or not.

[1]: https://youmatter.world/en/plane-or-cars-which-means-of-tran...

[perl4ever]

"It's the difference between able to go for the day or not"

Which points to how increases in capability and efficiency can stimulate demand, which could be a bad thing from an environmental perspective.

[melling]

And in the meantime, enough emissions from fossil fuels to generate electricity is emitted every year to cover a couple decades of flying.

[mrpopo]

This comment makes no sense because it doesn't state how many people get electricity and how many people fly.

The carbon footprint of one transatlantic flight is on the same order of magnitude as one person's yearly electricity consumption.

People who fly every year can substantially reduce their carbon footprint by not flying, people who already don't fly every year (the majority of the population) can't.

[choeger]

The climate does not care how many people caused the co2 emissions.

[mrpopo]

The climate system itself doesn't, but the total carbon budget has to be allocated to and split between 7 billion people one way or another.

What is a fair split?

Of course, if you want to keep flying at 800 km/h around the globe AND get power for your home's computers and 4k TV, you will have to advocate for cutting electricity AND blocking air transport of some other people until their coal plants are powered with solar panels. It's your right to decide so, but you have to admit it that it's unethical.

[usrusr]

People care. And even if you somehow think they should not you are in no position to decide what they care about.

[revax]

Almost the entirety of emissions are made up of 5% when you decompose by sector.

There is no silver bullet for reducing your carbon footprint. You should lower emissions for all industries at the same time.

[jpeanuts]

This is a very important idea. On a global scale this idea has been codified as "climate stabilzation wedges": https://johncarlosbaez.wordpress.com/2010/11/16/stabilizatio...

Each "wedge" is one method of reducing net CO2 output by 1 gigaton/year by 2054. Each wedge is a major economic and technological undertaking. Current estimates are that 13 wedges would be needed to limit CO2 to below 500 ppm. We have currently implemented 0 wedges.

[melling]

“ 4. Efficient coal plants: raise the efficiency of coal power plants to 60%. In 2004, when they wrote their paper, “coal plants, operating on average at 32% efficiency, produced about one fourth of all carbon emissions”

Coal is 25% of carbon emissions. We could have reduced this 2 decades ago. Instead we’re quibbling over 2.5% of emissions.

[pengaru]

> There are over 100,000 flights daily. They account for about 2.5% of CO2 emissions yearly.

The generally accepted emissions weighting factor for aviation co2 emissions is ~2.6. So it's more like 6.5%, and growing fast.

[tda]

Just to clarify: in the cases of high-altitude airliners which frequently fly near or in the stratosphere, non-CO2 altitude-sensitive effects may increase the total impact on anthropogenic (human-made) climate change significantly

https://en.wikipedia.org/wiki/Environmental_impact_of_aviati...

[lm28469]

Are there any studies comparing the impact of burning fuel at sea level VS at cruising altitude?

Also, it's not all about co2. I'm quite sure planes release a lot of other nasty things.